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‘Rain Man’-like brains mapped with network analysis

March 1, 2013

The 3D structural connectome of seven adults without a corpus callosum, a top genetic cause of autism. The larger, redder circles represent the hubs of the whole-brain network — the regions with the greatest number of connections to other regions. (Credit: Julia P. Owen et al.)

Researchers at UC San Francisco and UC Berkeley have mapped the three-dimensional global connections within the brains of seven adults who have genetic malformations that leave them without the corpus callosum, which connects the left and right sides of the brain.

These “structural connectome” maps, which combine hospital MRIs with the mathematical tool known as network analysis, reveal new details about the condition known as agenesis of the corpus callosum, one of the top genetic causes of autism. The condition was part of the mysterious brain physiology of Laurence Kim Peek, the remarkable savant portrayed by Dustin Hoffman in the 1987 movie “Rain Man.”

While some people born with agenesis of the corpus callosum are of normal intelligence and do not have any obvious signs of neurologic disease, approximately 40 percent of people with the condition are at high risk for autism. Given this, the work is a step toward finding better ways to image the brains of people with the condition, said Pratik Mukherjee, MD, PhD, a professor of radiology and biomedical imaging at UCSF who was the co-senior author of the research.

Understanding how brain connectivity varies from person to person may help researchers identify imaging biomarkers for autism to help diagnose it and manage care for individuals. Currently autism is diagnosed and assessed based on cognitive tests, such as those involving stacking blocks and looking at pictures on flip cards.

While the new work falls short of a quantitative measure doctors could use instead of cognitive testing, it does offer a proof-of-principle that this novel technique may shed light on neurodevelopment disorders.

“Because you are looking at the whole brain at the network level, you can do new types of analysis to find what’s abnormal,” Mukherjee said.

The connection between the brain hemispheres and autism

Agenesis of the corpus callosum can arise if individuals are born missing DNA from chromosome 16 and often leads to autism.

Scientists have long puzzled over what the link is between this disorder and the autistic brain, said co-senior author of the paper Elliott Sherr, MD, PhD, professor of neurology and genetics especially since not all people with this malformation develop autism.

Doctors believe this is because the brain has a rich capacity for rewiring in alternative ways.

Pursuing this question, Mukherjee and Sherr turned to MRI and the mathematical technique of network analysis, which has long supported fields like civil engineering, helping urban planners optimize the timing of traffic lights to speed traffic. This is the first time network analysis has been applied to brain mapping for a genetic cause of autism.

The brain offers a significantly complicated challenge for analysis because, unlike the streets of a given city, the brain has hundreds of billions of neurons, many of which make tens of thousands of connections to each other, making its level of connectivity highly complex.

By comparing the seven rain man-like brains to those of 11 people without this malformation, the scientists determined how particular structures called the cingulate bundles were smaller and the neurons within these bundles were less connected to others in the brain. They also found that the network topology of the brain was more variable in people with agenesis of the corpus callosum than in people without the malformation.

Comments (10)

I’ve been informally but rather conclusively diagnosed as having Aspergers, albeit a fairly mild case. I have a memory, however, of being able to instantly do long division around the 3rd grade. Then I had some flu-like illness ~1957 in which I ran a high fever that included hallucinations. Afterwards I was no longer able to do the long division. As I’ve gotten older, my ability to do simple arithmetic operations in general has seriously declined, although my general mental capability does not seem to have changed very much. I’m now wondering if this is all part of the same pattern.

Why are there connections visible between the cerebral hemispheres? And yes, I know the bulbs, hippocampus, and thalamus have commissural connections, but none so high up in the cerebrum as shown in the video.

This study will provide new therapy techniques used by speech pathologists in the future to treat clients with Autism. It will provide professionals who work with these clients more efficient and more interesting approaches to treatment .

My research indicates that the corpus callosum may pay a kee role in coordination, effecting shuch thigs as whether the subject can consistently ht a two handed free throw, or his or her golf drive wil go straight down the fairway or slice or hook. See my book, Fingerprints and Behavior (2012). Would love to coordiate with this research. However, question whether can find anyone in western academia who might collaborate with such as me.

Could the Corpus Callosum be the “valves” in our brain that exclude too much information about the world around us so that our present neurology can process it, and our biology function? Maybe Evolution will go along the road of eliminating the C.C., and then we will be trascending humans?

Eliminating the C.C.? Well… Looking at some children of friends and autists of my generation I would say autism does not lead to greater reproductive success, which ultimately decides which traits make it to the next generation.
But maybe rainman turns you on…. :)

Beatriz, are you speaking of the obviation of the perceptual ‘reducing valve’ allowing the realization of Mind at Large, a la Aldous Huxley? If it becomes possible to move in that direction, while maintaining a functional level of coherency regarding conscious processes, or to simply ‘toggle’ between the funneled mind and Mind at Large without autism or drugs playing a role, I would be very interested.
If evolution brings this about, I imagine it will be technological rather than strictly biological. And with the Cloud available as well as our sensory inputs.. The Mind at Massive, perhaps? Further, with the future ability to form connections between other minds, what could two Minds at Large conceive of? Four? Ten-thousand?
Woof.

It’s actually severed on purpose as a cure for certain conditions. Much study has been done with those people to understand what effects it has. One study that I remember had the patients view two different images flashed to the two eyes separately. The two hemispheres process information differently. Since they aren’t connected anymore all sorts of bizarre effects could be observed. It doesn’t confer any savant abilities.